Work it out.
Understand the answer.

Press Enter to calculate. Use ^ for powers and sqrt(9) for square roots. Percent always means ÷ 100: 50% = 0.5, so 200 * 10% = 20.

Results use up to 10 significant digits. Use parentheses to group values; -2^2 = -4, while (-2)^2 = 4.